Answer:

Step-by-step explanation:
Given
--- The variation

Required
Determine the constant of proportionality (k)

Express as an equation

Multiply both sides by 

Make k the subject

Given that: 
We have:



This can be represented as:
Answer:
(-∞,4)
Step-by-step explanation:
the value is going down from the right until it reaches the vertex
Answer:
3 times
Step-by-step explanation:
The lowest common multiple of 3, 8, and 12 is 24.
Therefore they all hoot together at the 24th hour, 48th(24×2) hour, 72nd(24×3)hour. making 3 times before the 80th hour
Answer:
c = 15d + 30
Step-by-step explanation:
Hey there!
This can be represented by an equation of a line, where the number of days is our x-values(d), and the price is our y-values(c).
The price for one day ($45) and the price for 4 days($90) are specific points on that line.
The points are (1, 45) and (4, 90).
We can first find the slope of the line:
- As the price rises 45, the days increase by 3
- Slope = rise/run
- Slope = 45/3
- Slope = 15
Now we can find the base price, by plugging the slope and a point into the equation y = mx + b.
Solve for b:
- y = mx + b
- 45 = 15(1) + b
- 45 = 15 + b
- 30 = b
The base price (b) is 30.
The equation is 